The Onbashira FestivalWhy do people risk their lives riding a huge log down a steep hill? "Tradition," say the Japanese. The Onbashira Festival is one of the strangest, and most dangerous, festivals in Japan. It has been held ever six years for 1,200 years.As part of each fest, four shrine buildings rebuilt at Suwa City, near Nagano.The "Onbashira" is an enormous fir tree measuring 17 meters or more in length, 1 meter in diameter, and weighing up to 12 or 13 tons.